Vista 32 Rebooting more frequently

I have had trouble with my custom built pc for awhile now. It started out as Firefox freezing and hanging in task manager processes. Sometimes a long waited restart worked the other half of the time a hard reset was needed. It quickly got more and more frequent. Now my entire OS is rebooting (every time) after fully loading to desktop. I have ran memory tests and keep drivers updated because I am a lifelong gamer. I also keep the hardware updated every three years. No problems have been found with memory.

OS is Vista Ultimate 32 bit if you know of any diagnostic tools I can use.
current hardware:
intel q6600 quad w/OCZ Vendetta 2
EVGA nForce 750i SLI FTW
2x EVGA e-GeForce 8800 GTS
Corsair DDR2 2x 4gb
Antec TruePower Quattro 1000
X-Fi Platinum Fatal1ty Champion Series

I monitor heat using the nvidia monitoring software everything stays in safe range and I keep the system clean. I noticed my usually cool running system had a heat spike on one of my video cards. Luckily I had SLI turned off because I was playing WoW at the time. Usually 68-70 C while gaming awhile. It shot up to 95 C. So I shut down. Since then I have had constant reboots when the desktop just finishes loading background software.

My motherboard has codes to see what is being read it gets to the final boot code no problem. I did have a hardware warning light go off and it is fine since taking out one of my video cards.

I really hope you guys can help me. I am totally out of ideas on what to do next. I tried restore to previous windows. Hard drives checked out fine with chkdsk. I do know this new apartment has non-grounded outlets and the landlord is being notified. It still runs great under safe mode w/networking.

Any ideas?